Publications des scientifiques de l'IRD

Soria-Hoyo C., Valverde J. M., Roche Olivier. (2019). A laboratory-scale study on the role of mechanical vibrations in pore pressure generation in pyroclastic materials : implications for pyroclastic flows. Bulletin of Volcanology, 81 (2), art. 12 [12 p.]. ISSN 0258-8900.

Titre du document
A laboratory-scale study on the role of mechanical vibrations in pore pressure generation in pyroclastic materials : implications for pyroclastic flows
Année de publication
2019
Type de document
Article référencé dans le Web of Science WOS:000457480700001
Auteurs
Soria-Hoyo C., Valverde J. M., Roche Olivier
Source
Bulletin of Volcanology, 2019, 81 (2), art. 12 [12 p.] ISSN 0258-8900
The results of laboratory-scale experiments with ignimbrite material are reported and discussed. The ignimbrite material contained in a rotating drum is subjected to mechanical vibrations, simulating particle agitation at the base of a pyroclastic flow propagating on an irregular substrate. It is observed that vibrations lead to a severe decrease of internal friction, evidenced by a drastic drop of the avalanche angle of the material in the rotating drum. We propose that acoustic streaming, a well-known phenomenon in engineering applications, operates in the ignimbrite material. Vibrations cause the development of rotational air flow around the particles, and in consequence, the enhancement of hydrodynamic viscous stresses promotes pore fluid pressure, which leads to dynamical weakening through fluidization. A fluid mechanical theoretical model accounts for the decrease of the friction coefficient of the ignimbrite material under a wide range of experimental conditions. It can be reasonably inferred that sustained high gas pore pressure resulting from mechanical agitation could be present in pyroclastic flows and might contribute to their high mobility.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Géophysique interne [066]
Localisation
Fonds IRD [F B010075106]
Identifiant IRD
fdi:010075106
Contact